Periodontal risk assessment determines the patient’s periodontal risk for further desease progression and subsequent tooth loss. According Lang and Tonetti (2003) the following six parameters provide the basis of the periodontal risk assessment.

Bleeding on probing (BOP) is determined by light probing to the bottom of the pocket with a standardized periodontal probe.

The result is a dichotomous positive or negative. The pressure applied should not exceed 0.25N (25g).

BOP is measured at four sites per tooth (mesio-buccal, mid-buccal, disto-buccal, and mid-oral). This is best done by quadrants, buccal measurements first, followed by oral.

The bleeding on probing score comprises the number of positive sites divided by the total number of sites multiplied by 100.

Four sites per tooth are gently probed (mesio-buccal, mid-buccal, disto-buccal, and mid-lingual). The number of pockets of 5mm or deeper are noted.

In assessing the patient’s risk for disease progression, the number of residual pockets with a probing depth of ≥5 mm is assessed as the second risk indicator for recurrent disease in the functional diagram of risk assessment. The scale runs in a linear mode with 2, 4, 6, 8, 10 and ≥12% being the critical values on the vector.

Individuals with up to 4 residual pockets may be regarded as patients with a relatively low risk, while patients with more than 8 residual pockets as individuals with high risk for recurrent disease.

For the purposes of the present risk assessment, a complete dentition comprises 28 teeth (wisdom teeth are excluded). Wisdom teeth which have drifted mesially to the site of second molars are counted as second molars.

The number of teeth lost from the dentition without the third molars (28 teeth) is counted, irrespective of their replacement. The scale runs also in a linear mode with 2, 4, 6, 8, 10 and ≥12 being the critical values on the vector.

Individuals with up to 4 teeth lost may be regarded as patients in a low risk category, while patients with more than 8 teeth lost may be considered as being in a high-risk category. Rationale for this stems from the significance of further tooth loss in terms of preservation of the function of the dentition.

The percentage of bone loss is estimated from radiographs of posterior teeth. The site with greatest loss provides the bone loss value.

Baseline bone level is taken to be 1mm apical to the CEJ. Bone loss is roughly estimated in increments of 10%. In cases where periapical radiographs are not available, bite-wings may be used. For the purposes of this approximation, bone loss is estimated at 10% per mm.

In assessing the patient’s risk for disease progression, the extent of alveolar bone loss in relation to the patient’s age is estimated as the fourth risk indicator for recurrent disease in the functional diagram of risk assessment.

The most substantiated evidence for modification of disease susceptibility and/or progression of periodontal disease arises from studies on Type I and Type II (insulin-dependent and non-insulin-dependent) diabetes mellitus populations.

It has to be realized that the impact of diabetes on periodontal diseases has been documented in patients with untreated periodontal disease, while, as of today, no clear evidence is available for treated patients. It is reasonable, however, to assume that the influence of the systemic conditions may also affect recurrence of disease.

In assessing the patient’s risk for disease progression, systemic factors, if known, are only considered as the fifth risk indicator for recurrent disease in the functional diagram of risk assessment. In this case, the area of high risk is marked for this vector. If not known or absent, systemic factors are not taken into account for the overall evaluation of risk.

Consumption of tobacco, predominantly in the form of smoking rather than snuffing or chewing, affects the susceptibility and the treatment outcome of patients with chronic periodontitis.

In assessing the patient’s risk for disease progression, environmental factors such as smoking must be considered as the sixth risk factor for periodontal disease progression in the functional diagram of risk assessment.

In spite of the paucity of available evidence relating cigarette smoking to impaired outcomes during supportive periodontal therapy (SPT), it seems reasonable to incorporate heavy smokers (≥20 cigarettes/day) in a higher risk group during maintenance.

While non-smokers (NS) and former smokers (FS: more than 5 years since cessation) have a relatively low risk for recurrence of periodontitis, the heavy smokers (HS: as defined by smoking more than one pack per day) are definitely at high risk.

Occasional smokers (OS: <10 cigarettes a day) and moderate smokers (MS: 10-19 cigarettes a day) may be considered at moderate risk for disease progression.

Download PDF: Lang & Tonetti (2003): Periodontal Risk Assessment (PRA) for Patients in Supportive Periodontal Therapy (SPT).

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